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Comment by freedman1611 | Hacker News Reader

As much as I love science fiction. In reality, even making it the nearest star is an impossible feat. Even traveling at the speed of light (which we are not even sure the human body can handle) it would take 100 years to reach our nearest star; let alone the nearest black hole. Even whether black holes exist, and what they really are is hotly debated. I think the idea of interstellar travel is futile, and we should focus on improving our quality of life here (free energy i.e. Telsa tech, transporting goods with electrogravitic vehicles, curing diseases, more scientific agricultural practices, easing access to education/job skills, etc).

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>Even traveling at the speed of light (which we are not even sure the human body can handle) it would take 100 years to reach our nearest star

Er, no. Travelling at c, it would take 4.5 years to get to our nearest star. The nearest (known) black hole is V616, 3,000 years of travel away if travelling @ c.

A bit pedantic but considering an acceleration and then deceleration of 1g, i can see the 100 year number being valid

It would take just under a year to accelerate to the speed of light at 1g. This doesn’t significantly change the four year number.

Even better, traveling at c, it would take exactly zero shipboard time. Space contracts infinitely for the sufficiently fast. Only outside viewers would see it take 4.5 years.

Except that you'd arrive inside a black hole because of relativity's impact on mass.

>Even traveling at the speed of light...it would take 100 years to reach our nearest star

The nearest star is a little over 4 light years away, not 100.

Let's compute travel time assuming constant acceleration to halfway point, and then constant deceleration to the destination. 'a' is acceleration and 'd' is distance to the star.

v(t) = at (velocity at time t)

∫v(t)dt = 0.5 a t^2 (distance traveled at time t)

0.5 a t^2 = 0.5 d ==> t = sqrt(d/a) (time to halfway point)

Plugging in d=4.5ly and a=9.81m/s yields 2.07 years to the halfway point, so that's just over 4 years total travel time at 1G.

The fun part is figuring out how far you go for each additional year. As experienced on board there's huge gains in distance for each extra year.

But looks like you forgot about relativity and that starts having a pretty big impact.

If you take relativity into account (which you should, it's how the universe works after all), traveling 4.37 light years at 1G acceleration/deceleration will take 3.58 years from the perspective of the people on the ship or 6 years from the perspective of those still on Earth[0].

You'd reach 95% of the speed of light, which would take 4 gigatons of TNT[1] (and 4 more to decelerate) if it's just you and your ship and energy source weight nothing. That's definitely science fiction. 100 years is optimistic.

[0] http://convertalot.com/relativistic_star_ship_calculator.htm...

[1] https://www.omnicalculator.com/physics/relativistic-ke?v=v:....

If we could travel at (just below) the speed of light, then getting to the next star would take somewhat under four years from the point of view of the travelers assuming an acceleration of 1g (or no noticeable time at all assuming serious magic, with close to infinite acceleration). Of course, the energy to make the acceleration is the big problem...

I think you're being down-voted because you are sort of wrong about the distances. We could probably get some people to another star. Why we would do that, or what we would tell them (with a five year communication delay) after they got there, is unclear.

For the record, I think your questioning of "what black holes really are" is prudent. The OP article is not prudent, firstly because any of its implications won't be realized for at least 3,000 years. Secondly because our challenge as a society is very much not speculating about this thing Hawking wrote about, and very much is trying to make any of these scenarios useful to us.

Which leads to my fringe opinion that we should try really hard to build a black hole, even if we're worried about it ending us.

"Fuckin' magnets. HOW DO THEY WORK?"

> "I think you're being down-voted because you are sort of wrong about the distances."

Or maybe it's because he proposed we dedicate our resources to violating the laws of thermodynamics ("free energy"...)

For clarification and in Tesla's defense: If I've correctly read some of the descriptions of his idea, it didn't involve "energy from nothing" and hence no obvious violation of thermodynamics. Rather, it involved (roughly) building huge antennas/lightning rods to tap into the natural electric potential (against ground) of the ionosphere.

As I understand it, the idea is simply impractical. But there's a huge Tesla fan base among the intersection of conspiracy theorists and amateur (pseudo)scientists who believe that Tesla's idea was scuttled and suppressed by Big Electric to protect their monopoly on generating electricity in harder ways.

I can't fathom why anybody in their right mind would choose to call their scheme "free energy", e.g. choose to associate themselves with perpetual motion nuts. We can get electrical energy from sunlight, which is pretty damn neat, and nobody calls that "free energy."

Any black hole we could conceivably create would completely evaporate in nanoseconds. There's even conjecture that the LHC may have created some already (although it's not probable, it's not entirely outside the realm of possibility). It's not like they stick around eating more once you make them.

We might be able to create our own spinning black hole gate :-P

What could possibly go wrong with that idea?

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